Serial changes of the susceptibility of epileptogenic focus during hippocampal kindling induced with low-frequency electrical stimulation in cats.

Cats were stimulated in the dorsal hippocampus with low-frequency square wave pulses. All subjects were kindled until generalized convulsion occurred. In the early stage of the kindling process, an increase in the interpulse interval and a decrease in the number of stimulating pulses required for the provocation of epileptic afterdischarge were observed, but in the late stage a decrease in the former and an increase in the latter were observed. It appears from these data that completion of hippocampal kindling is accompanied by a decrease in excitability at the site of stimulation subsequent to an increase in the same.